Effect of extracts from Spirulina platensis bioaccumulating cadmium and zinc on L929 cells.

The uptake of cadmium and zinc by Spirulina platensis was investigated using a laboratory culture of this cyanobacterium. The cells were treated with metal concentrations increasing from 0.5 to 2.0 mg L(-1), in order to evaluate their adsorption capacity and survival potential. Afterwards, the cytotoxicity of cell extracts bioaccumulating heavy metals was evaluated on cultured L929 mouse fibroblasts. Cadmium was removed with higher yield (84.0-88.7%) than zinc (54.5-68.0%) and the maximum specific removal of these metals was 1.82 and 2.60 mg g(-1), respectively. Cadmium bioaccumulating algal extracts caused higher cell mortality of L929 cells than zinc accumulating ones, with a clear dose-response trend. EC(50) estimated by Trimmed Spearman-Karber (TSK) method were 7.21 and 9.59cells mL(-1) for cadmium and zinc, respectively. The capability to accumulate heavy metals could have a remarkable importance for the utilization of algal species in human or animal feeding.